using UnityEngine;
using BaseGames.Core;
using BaseGames.Core.Events;

namespace BaseGames.Combat
{
    /// <summary>
    /// 抛射物管理器（单例 MonoBehaviour）。
    /// 缓存玩家 Transform，供追踪类抛射物注入目标引用。
    /// </summary>
    public class ProjectileManager : MonoBehaviour, IProjectileService
    {
        [SerializeField] private TransformEventChannelSO _onPlayerSpawned;

        private Transform _playerTransform;
        private readonly CompositeDisposable _subs = new();

        /// <summary>当前缓存的玩家 Transform，生成追踪弹时使用。</summary>
        public Transform PlayerTransform => _playerTransform;

        private void Awake()
        {
            if (ServiceLocator.GetOrDefault<IProjectileService>() != null) { Destroy(gameObject); return; }
            ServiceLocator.Register<IProjectileService>(this);
        }

        private void OnDestroy()
        {
            ServiceLocator.Unregister<IProjectileService>(this);
        }

        private void OnEnable()
        {
            _onPlayerSpawned?.Subscribe(OnPlayerSpawned).AddTo(_subs);
        }

        private void OnDisable()
        {
            _subs.Clear();
        }

        private void OnPlayerSpawned(Transform player) => _playerTransform = player;

        /// <summary>
        /// 完整初始化一枚 <see cref="HomingProjectile"/> 并注入追踪目标。
        /// </summary>
        public void LaunchHoming(HomingProjectile proj, Vector2 direction,
                                 ProjectileConfigSO config, DamageInfo damageInfo, int ownerLayer = 0)
        {
            if (proj == null || config == null) return;
            proj.Initialize(config, damageInfo, direction, ownerLayer);
            proj.SetTarget(_playerTransform);
        }
    }
}